Diode laser array coupling optic and system

Abstract

A single piece optic for coupling the output of a diode laser array into an optical fiber array is provided. The coupling optic has a planar back surface which, during use with a diode laser array, is positioned substantially parallel to the front face of the laser array. The coupling optic is fabricated from a single substrate and is comprised of a plurality of optical elements. Depending upon the technique used to fabricate the optical elements, the individual optical elements may be trapezoidally-shaped or rectangularly-shaped. The front surface of each optical element is tilted, thus preventing reflected laser radiation from resonating within the diode laser's emitters. Preferably the wedge angle for the tilted front surface is greater than 2 mrad, thus accomplishing the goal of limiting feedback into the emitters, and less than 4 mrad, thus reducing beam steering. Additionally each optical element is shaped to reduce the divergence of the emitters in the fast axis, thus allowing the output from each emitter to be effectively coupled into the corresponding optical fiber.

1. A laser system comprising:
 a diode laser array comprised of a plurality of emitters, wherein each of said plurality of emitters emits an output beam from an output facet, and wherein each of said output beams has a fast axis of divergence and a slow axis of divergence; and 
 a one piece coupling optic adjacent to said output facets of said plurality of emitters of said diode laser array, wherein said one piece coupling optic has a planar back surface which is substantially parallel to a front face of said diode laser array, and wherein said one piece coupling optic further comprises a plurality of optical elements corresponding to said plurality of emitters, wherein each of said plurality of optical elements has a tilted front surface, and wherein each of said plurality of optical elements is shaped to reduce said fast axis of divergence of said output beam of said corresponding emitter of said plurality of emitters; and an optical fiber array comprised of a plurality of optical fibers, wherein said plurality of optical fibers correspond to said plurality of optical elements and said plurality of emitters. 
 
   
   
     2. The laser system of  claim 1 , wherein said one piece coupling optic is interposed between said diode laser array and said optical fiber array. 
   
   
     3. The laser system of  claim 1 , wherein said tilted front surface of each of said plurality of optical elements is adjacent to said output facet of said corresponding emitter of said plurality of emitters, and wherein said planar back surface of each of said plurality of optical elements is adjacent to an input surface of said corresponding optical fiber of said optical fiber array. 
   
   
     4. The laser system of  claim 3 , further comprising a first AR coating on said tilted front surface of each of said plurality of optical elements and a second AR coating on said planar back surface of each of said plurality of optical elements. 
   
   
     5. The laser system of  claim 1 , wherein a diameter corresponding to each of said plurality of optical fibers of said optical fiber array is approximately equal to a width corresponding to each of said plurality of emitters of said diode laser array. 
   
   
     6. A The laser system comprising:
 a diode laser array comprised of a plurality of emitters, wherein each of said plurality of emitters emits an output beam from an output facet, and wherein each of said output beams has a fast axis of divergence and a slow axis of divergence; and 
 a one piece coupling optic adjacent to said output facets of said plurality of emitters of said diode laser array, wherein said one piece coupling optic has a planar back surface which is substantially parallel to a front face of said diode laser array, and wherein said one piece coupling optic further comprises:
 a plurality of optical elements corresponding to said plurality of emitters,wherein each of said plurality of optical elements has a tilted front surface, and wherein each of said plurality of optical elements is shaped to reduce said fast axis of divergence of said output beam of said corresponding emitter of said plurality of emitters, wherein a wedge angle corresponding to said tilted front surface of each of said plurality of optical elements is greater than 2 mrad and less than 4 mrad. 
 
 
   
   
     7. The laser system of  claim 6 , wherein each of said plurality of optical elements is trapezoidally-shaped. 
   
   
     8. The laser system of  claim 6 , wherein each of said plurality of optical elements is rectangularly-shaped. 
   
   
     9. The laser system of  claim 6 , wherein said tilted front surface of each of said plurality of optical elements is adjacent to said output facet of said corresponding emitter of said plurality of emitters. 
   
   
     10. The laser system of  claim 6 , further comprising a coupling optic mounting bracket, wherein said one piece coupling optic is bonded to said coupling optic mounting bracket, and wherein said coupling optic mounting bracket is attached to said diode laser array. 
   
   
     11. The laser system of  claim 6 , further comprising:
 a coupling optic mounting bracket, wherein said one piece coupling optic is bonded to said coupling optic mounting bracket; 
 a diode laser array mounting member, wherein said diode laser array is attached to said diode laser array mounting member; and 
 wherein said coupling optic mounting bracket is attached to said diode laser array mounting member. 
 
   
   
     12. The laser system of  claim 6 , further comprising:
 a first AR coating applied to said tilted front surface of each of said plurality of optical elements of said one piece coupling optic, wherein said tilted front surface of each of said plurality of optical elements is adjacent to said output facet of said corresponding emitter of said plurality of emitters; and 
 a second AR coating applied to said planar back surface of each of said plurality of optical elements. 
 
   
   
     13. A laser system comprising:
 a diode laser array comprised of a plurality of emitters, wherein each of said plurality of emitters emits an output beam, and wherein each of said output beams has a fast axis of divergence and a slow axis of divergence; 
 an optical fiber array comprised of a plurality of optical fibers, wherein said plurality of optical fibers corresponds to said plurality of emitters; and 
 a one piece coupling optic interposed between said diode laser array and said optical fiber array, wherein said one piece coupling optic has a planar back surface which is substantially parallel to a front face of said diode laser array, and wherein said one piece coupling optic further comprises:
 a plurality of optical elements corresponding to said plurality of emitters and said plurality of optical fibers, wherein each of said plurality of optical elements has a tilted front surface and a planar back surface, said tilted front surface adjacent to an emitter output facet of said corresponding emitter of said plurality of emitters and said planar back surface adjacent to an input surface of said corresponding optical fiber of said optical fiber array, and wherein each of said plurality of optical elements is shaped to reduce said fast axis of divergence of said output beam of said corresponding emitter of said plurality of emitters. 
 
 
   
   
     14. The laser system of  claim 13 , wherein each of said plurality of optical elements is trapezoidally-shaped. 
   
   
     15. The laser system of  claim 13 , wherein each of said plurality of optical elements is rectangularly-shaped. 
   
   
     16. The laser system of  claim 13 , further comprising a first AR coating on said tilted front surface of each of said plurality of optical elements and a second AR coating on said planar back surface of each of said plurality of optical elements. 
   
   
     17. The laser system of  claim 13 , wherein a diameter corresponding to each of said plurality of optical fibers of said optical fiber array is approximately equal to a width corresponding to each of said plurality of emitters of said diode laser array. 
   
   
     18. The laser system of  claim 13 , wherein a wedge angle corresponding to said tilted front surface of each of said plurality of optical elements is greater than 2 mrad and less than 4 mrad. 
   
   
     19. The laser system of  claim 13 , further comprising a coupling optic mounting bracket, wherein said one piece coupling optic is bonded to said coupling optic mounting bracket, and wherein said coupling optic mounting bracket is attached to said diode laser array. 
   
   
     20. The laser system of  claim 13 , further comprising:
 a coupling optic mounting bracket, wherein said one piece coupling optic is bonded to said coupling optic mounting bracket; 
 a diode laser array mounting member, wherein said diode laser array is attached to said diode laser array mounting member; and 
 wherein said coupling optic mounting bracket is attached to said diode laser array mounting member.